Overall objectives of the proposed work are the isolation and identification of fungi, especially members of the penicillia, that are toxic and/or carcinogenic, determination of the mycotoxicosis produced in experimental animals and the preparation of toxic materials with the chemical identification of the toxins and carcinogens. Specifically, the mycotoxicoses produced by citrinin and ochratoxin A will be studied in the dog and guinea pig along with a study of the possible synergistic activities of the two mycotoxins when combined. Components of the study will include clinical, clinicopathologic, histopathologic and ultrastructural evaluations. These studies are indicated because of the established production of ochratoxin A and citrinin by isolates of Penicillium viridicatum and other fungi. Specific attention will be directed to the determination of the unidentified toxin in toxic cultures of the fungus Penicillium viridicatum and the confirmation of its carcinogenic activity.